Status: This license was in effect between 13 May 2015 and 31 December 2022. It was replaced by https://www.w3.org/copyright/software-license-2002/
Changes since the previous document
This version makes clear that the license is applicable to both software and text, by changing the name and substituting "work" for instances of "software and its documentation." It moves "notice of changes or modifications to the files" to the copyright notice, to make clear that the license is compatible with other liberal licenses.